CPU PLL Voltage, what effect does it have?

[Devrij]

As in title really, I'm stable at 4.7GHz on my 2500k, but you always wonder if you could get more out of it. I know I hit a wall at 4.9GHz and don't want to push more Vcore through it, but I was wondering whether increasing PLL voltage could help me get past that.

So, considering all the clockspeeds are generated from the static 100Mhz bclk, what effect does PLL overvolting have on a SB overclock? I've read it helps keep high FSB overclocks stable, but am I right in thinking that I'm not raising FSB when I increase the cpu multi?

It was all much simpler on S775 lol

 

[Surveyor]

but am I right in thinking that I'm not raising FSB when I increase the cpu multi?

Yes.

As in title really, I'm stable at 4.7GHz on my 2500k, but you always wonder if you could get more out of it. I know I hit a wall at 4.9GHz and don't want to push more Vcore through it, but I was wondering whether increasing PLL voltage could help me get past that.

CPU PLL Voltage: Generally this doesn't need changing at all, although if increasing the CPU Voltage or the two VCC options doesn't work, it's worth a try. Using anything over 2V isn't recommended, but 1.9V can help to stabilise an overclock.

VCC/VCCIO/CPUIO: Vcc is the voltage at the IO (Input/Output) terminals to the CPU. Generally at 4GHz or under this doesn't need to be adjusted, but at 4.5GHz it can require a small bump to between 1.15V and 1.2V, depending on the quality of your CPU. Using over 1.2V should only be necessary if you're pushing the CPU toward 5GHz or more. Equally, if you're using the maximum memory multiplier, you will likely require about 1.25V here. Using over 1.4V is not recommended at all - you have been warned!

VCCSA: The 'System Agent' is a facilitator unit in the CPU itself, and its Vcc (essnetially, voltage') is related to the Vcc IO above. It's default voltage is under 1V. The same rules apply here as above though, the only difference is if you're testing how far the Base Clock will go, then as much as 1.3V, or even 1.35V will be needed, but that's only recommend for benchmarking with appropriately strong cooling and not long term use. using over 1.4V is not recommended at all.

Lifted from here:

http://www.bit-tech.net/hardware/cpus/2011/01/07/how-to-overclock-the-intel-core-i5-2500k/1

 

[1Day]

You might find it too your advantage to try to lower your PLL voltages. Auto is normally 1.8 or higher. Yet for 5GHz plus I have had best results with my PLL at 1.76.

Further if you do wish to get beyound the 5GHz barrier you will most certainly need a BIOS that has the PLL overrider enable option.


Enjoy

 

[1kiwi]

Further if you do wish to get beyound the 5GHz barrier you will most certainly need a BIOS that has the PLL overrider enable option.
Enjoy

Do you mean internal PLL overvoltage 1day?

Also, what voltages are you generally running for 4.9/5Ghz Prime Blend Stable?

I'm on:

Vcore: 1.35 0.1 offset (1.44 under load)
Vtt: 1.16
PLL: 1.9
PLL overvoltage enabled
LLC: On

 

[Devrij]

Yes.



CPU PLL Voltage: Generally this doesn't need changing at all, although if increasing the CPU Voltage or the two VCC options doesn't work, it's worth a try. Using anything over 2V isn't recommended, but 1.9V can help to stabilise an overclock.

VCC/VCCIO/CPUIO: Vcc is the voltage at the IO (Input/Output) terminals to the CPU. Generally at 4GHz or under this doesn't need to be adjusted, but at 4.5GHz it can require a small bump to between 1.15V and 1.2V, depending on the quality of your CPU. Using over 1.2V should only be necessary if you're pushing the CPU toward 5GHz or more. Equally, if you're using the maximum memory multiplier, you will likely require about 1.25V here. Using over 1.4V is not recommended at all - you have been warned!

VCCSA: The 'System Agent' is a facilitator unit in the CPU itself, and its Vcc (essnetially, voltage') is related to the Vcc IO above. It's default voltage is under 1V. The same rules apply here as above though, the only difference is if you're testing how far the Base Clock will go, then as much as 1.3V, or even 1.35V will be needed, but that's only recommend for benchmarking with appropriately strong cooling and not long term use. using over 1.4V is not recommended at all.

Lifted from here:

http://www.bit-tech.net/hardware/cpus/2011/01/07/how-to-overclock-the-intel-core-i5-2500k/1

Ah cheers, just what I was looking for